The present invention relates generally to a trailer tipper for dumping a trailer containing a dumpable material, and more particularly, to an improved portable rotary tipper and an improved method for emptying a trailer container of a type hauled by tractor-trailers or semi-trucks. For example, such a tipper and method for emptying trailers may be used to efficiently remove refuse from trailers at a landfill site.
Other portable trailer tippers have been used to dump garbage from semi-truck haulable trailers at landfill sites. These earlier tippers raise the front end of the trailer containers to dump the contents from the back end of the trailer. Such tippers usually have an elongated deck with a tipping frame mounted thereon. Each trailer must be carefully backed by a tow truck up ramps, and then onto the tipping frame, where it is disconnected from the tow truck. The front end of the tipping frame is then pivoted upwardly from the deck to dump the contents of the trailer through a door at the rear of the trailer. After dumping, the tipping frame is lowered, the empty trailer is hitched to the tow truck, and the trailer is towed from the tipper. These earlier tippers and trailers suffer a variety of disadvantages.
For example, tipping an elongate semi-trailer longitudinally raises the front end of the trailer to a considerable height above the ground. Unfortunately, these earlier tippers typically have both a high center of gravity and a high profile during tipping. Either of these conditions may lead to instability if the tipper shifts upon soft ground at a landfill site, or if high winds occur during the tipping operation.
Furthermore, the back doors on these earlier trailers offer only a relatively small passageway for dumping, so refuse tends to accumulate in a relatively small area adjacent the tipper. The refuse pile may quickly grow to obstruct the flow of material from the trailer rear doors. It is often necessary to use a bulldozer to clear the pile away from the tipper after each dumping cycle.
The rear doors of a trailer may also become jammed from within during dumping. Large objects or sticky substances in the refuse may clog the rear door, causing a bottleneck in the dumping. Furthermore, the back doors on these earlier refuse trailers are commonly required to be specially sealed during railroad or highway transport. For instance, trailer containers that are transported on railroads are required to have doors sealed to withstand a 20-foot drop crash, when fully loaded, without opening or leaking. Repeated door-sealing operations eventually damage the doors so that they must be replaced frequently, typically after about six dumping cycles.
Thus, a need exists for an improved trailer tipper and method for dumping the contents from a trailer that is directed toward overcoming, and not susceptible to, the above limitations and disadvantages.